1. Field of the Invention
The present invention relates to a tape printing device for printing a desirable series of characters on a tape and cutting the tape to a label of a desirable length, and also to a tape cartridge used in the tape printing device for receiving a tape therein. More specifically, the invention is to a technique attaining accurate but simple printing on a variety of tapes such as different widths, colors, and materials.
2. Description of the Related Art
Devices for printing a desirable series of characters on a surface of an adhesive tape, which has a rear face with an adhesive previously applied thereon, and cutting the tape to a label of a desirable length (hereinafter referred to as tape printing device) are generally known and conveniently used in houses and offices. Such a tape printing device does not require any additional or specific peripheral equipment, but realizes efficient direct printing of characters or symbols on an adhesive tape and cutting of the tape to an adhesive label. With this tape printing device, for example, a user can print a title of a business file, music, or movie on a tape and apply an adhesive label with the title onto a spine of a file or a back of an audio cassette tape or a video tape conveniently at any desirable place.
A variety of tape cartridges including tapes of different widths and ink of different colors are commercially available to meet various demands for such a tape printing device. The tapes in the tape cartridge range from a relatively wide tape preferably applicable to a thick spine of a large file to a relatively narrow tape as of several millimeters in width desirably applicable to a narrow back of an audio cassette tape. The tape printing device itself has been improved greatly to have a plurality of functions to realize beautiful printing and allow selection of a desirable printing style.
The inventors have found that it is unexpectedly difficult to obtain desirable labels using the conventional tape printing device with tapes of significantly different widths. When the difference in the tape width is relatively small, such a problem is not clearly recognized.
A variety of tapes and printing styles make operation and control of the tape printing device undesirably complicated, thus damaging the essential advantage of the tape printing device that realizes simple label printing. When printing of a large point number is implemented while a tape cartridge with a narrow tape is set in the tape printing device, or when a series of characters of a standard font are changed to have a wider font, the characters may be mistakenly printed out of the tape width or a predetermined length.
In the tape printing device, a desirable series of characters and symbols are printed on a certain length of a long tape, and the certain length of the tape with the print thereon is then cut to a label of a desirable length manually or automatically. Left and right margins in a longitudinal direction of the tape on the cut tape (hereinafter referred to as the label) are respectively defined as feeding distances of the tape from a cut end of the tape to a starting position of printing and from an end position of printing to a cutting position. In the conventional tape printing devices, the lengths of the left and right margins are generally fixed. The tape used in the tape printing device has a peeling sheet attached on a rear face thereof to become adhesive when the peeling sheet is peeled off, and is formed to allow thermal transfer printing. This makes the tape relatively expensive, and the margins on the tape are thereby fixed to have lengths as small as possible.
Each label includes a printed portion of desirable characters and left and right margins. Since the lengths of the margins are fixed in the conventional tape printing device, the ratio of the printed portion to the margins can not be determined arbitrarily by the user and may be unbalanced.
A mechanism allowing the user to specify the lengths of margins has been proposed. When a plurality of tapes of different widths are used, however, optimal setting of margins for a tape of a certain width is not suitable for other tapes of different widths. Setting of the margin lengths is thus required every time when the tape cartridge is changed to have a tape of a different width.
The tape printing device generally uses a thermal transfer printing mechanism to make the printing mechanism and thereby the whole device preferably compact. For the same purpose, a fixed printing head of a sufficient printing range is used to implement printing.
In the thermal transfer printing, an ink ribbon as well as the tape is accommodated in the tape cartridge so as to be overlapped with each other at a position of a platen roller. When the tape cartridge is set in the tape printing device to ready for printing, the tape and the ink ribbon are held at the overlapped position between the thermal head and the platen roller. When power is supplied to the printing head synchronously with feeding of the tape, ink on the ink ribbon is melted and transferred onto the surface of the tape for printing.
When the user arbitrarily selects the tape width, a printing range of the thermal head may become greater than the actual width of the tape set in the device, that is, characters may be printed outside the tape width.
A method of prohibiting execution of printing has been proposed to prevent waste of labels. In the compact tape printing device, however, a display unit is made relatively small and insufficient for informing the user of a detailed cause of such prohibition. The user needs to operate a layout display function to find the cause.
Another proposed method executes printing irrespective of the printing range out of the tape width to obtain a label with partly missing characters. The defective label informs the user of a cause of printing failure. There -are problems described below.
Even when the tape cartridge has a relatively narrow tape therein, the ink ribbon accommodated in the tape cartridge has a width equal to or greater than a printing range of the printing head. This makes the ink ribbon to be positioned between the printing head and the platen roller and prevents the printing head to be directly slid against the platen roller.
When the printing range exceeds the tape width, ink on the ink ribbon is undesirably applied on the platen roller. This leads to unintentional spots on a rear face of the label when another tape of a greater width is subsequently used for printing. Ink adhering to the platen roller changes the diameter of the platen roller to vary the left and right margins of the tape or the character size or to cause mechanical troubles.
According to the above results, the user of the conventional tape printing device should change the form, the font size, and the margin setting every time when a tape of a different width is used for printing. The user also needs to check whether the tape cartridge set in the tape printing device includes a tape of a certain width corresponding to the printing range to prevent characters from being printed out of the tape width.